﻿#region The MIT License (MIT)
// The MIT License (MIT)
// Copyright (c) 2010 - 2013 Sovacode LLC
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated 
// documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or substantial portions
// of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
// BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using Sovacode.RubiksCube.Common.Exceptions;

namespace Sovacode.RubiksCube.Common.Base
{
    /// <summary>
    /// Static class helper to work with <see cref="Expression{TDelegate}"/>
    /// </summary>
    public static class ExpressionHelper
    {
        /// <summary>
        /// Extracts name from <see cref="Expression{TDelegate}"/>
        /// </summary>
        /// <typeparam name="T">Type of returning result of function <see cref="Func{TResult}"/></typeparam>
        /// <param name="expression"><see cref="Expression{TDelegate}"/></param>
        /// <returns>Property Name</returns>
        public static string ExtractName<T>(this Expression<Func<T>> expression)
        {
            return ExpressionToString(expression);
        }

        /// <summary>
        /// Extracts name from <see cref="Expression{TDelegate}"/>
        /// </summary>
        /// <param name="expression"><see cref="Expression{TDelegate}"/></param>
        /// <returns>Property Name</returns>
        public static string ExtractName(this Expression<Action> expression)
        {
            return ExpressionToString(expression);
        }

        /// <summary>
        /// Extracts names from an array of <see cref="Expression{TDelegate}"/>
        /// </summary>
        /// <typeparam name="T">Type of Property</typeparam>
        /// <param name="expressions">Properties as <see cref="Expression{TDelegate}"/></param>
        /// <returns>Property Name</returns>
        public static string[] ExpressionToString<T>(params Expression<Func<T>>[] expressions)
        {
            if (expressions == null || !expressions.Any())
            {
                throw new ExpressionNullException();
            }

            IList<string> expressionNames = new List<string>(expressions.Count());

            foreach (var expression in expressions)
            {
                expressionNames.Add(ExpressionToString(expression));
            }

            return expressionNames.ToArray();
        }

        /// <summary>
        /// Extracts name from <see cref="Expression{TDelegate}"/>
        /// </summary>
        /// <typeparam name="T">Type of Property</typeparam>
        /// <param name="expression">Property as <see cref="Expression{TDelegate}"/></param>
        /// <returns>Property Name</returns>
        public static string ExpressionToString<T>(Expression<Func<T>> expression)
        {
            if (expression == null)
            {
                throw new ExpressionNullException();
            }

            return ((MemberExpression) expression.Body).Member.Name;
        }

        /// <summary>
        /// Extracts name from <see cref="Expression{TDelegate}"/>
        /// </summary>
        /// <param name="expression"><see cref="Expression{TDelegate}"/></param>
        /// <returns>Method Name</returns>
        public static string ExpressionToString(Expression<Action> expression)
        {
            if (expression == null)
            {
                throw new ExpressionNullException();
            }

            return ((MethodCallExpression)expression.Body).Method.Name;
        }
    }
}